Collaborative Research: Antiferromagnetic Spin-Flop Transitions in Heusler-Piezoelectric Systems Induced via Voltage

Northeastern University, Boston MA

Investigators

Abstract

Developing new materials with unique magnetic and electronic properties is at the forefront of materials science and nanotechnology. In this project, materials with a unique combination of magnetic, electronic, and strain properties are studied to advance future applications in ultrahigh-frequency (Terahertz) transistors and wireless communications, which are necessary to meet the ever increasing size of data sets and the speed of data transmission. The midshipmen (undergraduates at the Naval Academy) involved in this project will participate in educational outreach of underrepresented groups in the sciences - including young women in the local areas. This project will also serve as a training ground for midshipmen and undergraduates in magnetic nanostructures and information technology. Multiferroic materials have been proposed for an array of applications due to their binary or ternary co-existing magnetic spin, electric dipole, and ferroelastic properties. These multiferroic properties have been found in single phase compounds, however, they are rare and will have operating limitations in future devices, including low operational temperatures where the multiferroic properties co-exist. Compared to single-compound multiferroics, the arena is far larger for artificial multiferroics containing composites of dissimilar materials. This project focuses on coupling versatile magnetoelastic Heusler compounds strain-coupled to a piezoelectric substrate (e.g. PMN-PT) to mimic single-phase antiferromagnetic (AFM) multiferroic properties for THz AFM spintronics. Heterostructures will be grown using molecular beam epitaxy (MBE) and sputtering. Various methods including polarized beam reflectometry, synchrotron X-ray diffraction, and X-ray magnetic circular dichroism will be employed to fully investigate the voltage control of the crystallographic and magnetic structures. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.